It is hypothesized that Stem Cell Factor (SCF) when administered by subcutaneous injection to patients with heavily pretreated lymphoma in addition to Granulocyte-Colony Stimulating Factor (G-CSF) will allow for enhanced mobilization of peripheral stem cells (PSC) and more rapid engraftment of white blood cells and platelets following myeloablative therapy. The specific aims are: 1) To evaluate CD34+ stem cell collection in patients who receive G-CSF +/- SCF as movilization prior to PSC collection; 2) To assess the toxicity of stem cell factor when administered by subcutaneous injection; 3) To evaluate engraftment of peripheral stem cells mobilized with G-CSF +/- SCF following myeloablative chemotherapy/radiotherapy; 4) To assess quality of life in these patients.